Bearing means for a bolt action of a gun

ABSTRACT

A gun comprises a barrel, stock, receiver and a bolt slidable in the receiver. The bolt is provided with a plurality of bearing units which include ball elements mounted in a housing which are secured in recesses in the bolt. The ball elements engage the interior surface of the receiver to facilitate movement of the bolt. The firing pin of the bolt is also mounted for longitudinal movement by ball elements which also facilitate movement of the firing pin and reduce wear thereto.

United States Patent Spencer [451 Jan. 25, 1972 [54] BEARING MEANS FOR A BOLT ACTION OF A GUN [72] Inventor: William J. Spencer, 5501 Brookdale Drive, Brooklyn Park, Minn. 55007 [22] Filed: Mar. 10, 1970 211 Appl. No.: 18,081

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[56] References Cited UNITED STATES PATENTS 1,365,355 l/l92l Thompson ..42/l6A Primary ExaminerBenjamin A. Borchelt Assistant Examiner-C. T. Jordan Attorney-Williamson, Palmatier & Bains [5 7] ABSTRACT A gun comprises a barrel, stock, receiver and a bolt slidable in the receiver. The bolt is provided with a plurality of bearing units which include ball elements mounted in a housing which are secured in recesses in the bolt. The ball elements engage the interior surface of the receiver to facilitate movement of the bolt. The firing pin of the bolt is also mounted for longitudinal movement by ball elements which also facilitate movement of the firing pin and reduce wear thereto.

6 Claims, 9 Drawing Figures BEARING MEANS FOR A BOLT ACTION OF A GUN SUMMARY OF THE INVENTION It is an object of this invention to provide a gun having a bolt action with hearing units for the bolt to not only facilitate movement of the bolt but also to substantially reduce, if not eliminate, the need for a lubricant for the gun. The use of small bearing units for the bolt action further minimizes the tendency of the bolt to jam due to the presence of debris or the like in the receiver chamber, and these bearing units also minimize wear to the bolt. In some instances, the firing pin will also be supported by bearing units to facilitate movement of the firing pin and also to reduce wear thereto.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS FIG. I is a perspective view of a small caliber rifle having a slidable bolt action supported by the novel bearing means;

FIG. 2 is a fragmentary side elevational view of a portion of the gun illustrated in FIG. 1 with certain parts thereof broken away for clarity;

FIG. 3 is a perspective view of a bolt incorporating the novel bearing means;

FIG. 4 is a fragmentary cross-sectional view taken approximately along line 4-4 of FIG. 3 and looking in the direction of the arrows and illustrating a bearing unit of the bolt;

FIG. 5 is an enlarged cross-sectional view of the bearing unit illustrated in FIG. 4;

FIG. 6 is an enlarged fragmentary cross-sectional view similar to FIG. 5 but illustrating a modified form of the bearing unit;

FIG. 7 is a view similar to FIG. 6 but illustrating a further modified form of the bearing unit;

FIG. 8 is a view similar to FIG. 7 but illustrating a still further modified form of the bearing unit; and

FIG. 9 is a diagrammatic cross-sectional view of a bolt illustrating the firing pin thereof supported for movement by hearing units.

Referring now to the drawings and more specifically to FIG. 1, it will be seen that a small caliber rifle is there shown and is designated generally by the reference numeral 10. The rifle or gun 10 includes a barrel lI having a stock 12 secured thereto, and a trigger I3provided with a suitable trigger guard 14. The gun I0 also includes a receiver. 15 having a hollow interior which defines a receiver chamber 16 therein.

The receiver chamber I6 has an open rear end and communicates forwardly with the barrel to permit each round to be fired to be seated in the barrel in a well-known manner. The open rear end of the receiver chamber 16 is closed by a rear buffer member 17 which as shown is of generally tapered configuration. This rear buffer member has a knurled annular flange l8 thereon and is provided with an externally threaded sleeve portion 19 which projects forwardly interiorly of the receiver 15 and threadedly engages the internally rear threaded portion thereof. An elongated stem 20 extends interiorly of the sleeve portion 19 and is secured to the buffer member 17 by a threaded bolt 2 A helical spring 22 is positioned around the stem 20 and projects interiorly of the sleeve portion 19 and has one end thereof which engages the buffer member 17.

The forward end of the helical spring 22 engages the rear end portion of a slidable bolt 23, the latter having an opening 24 in the rear end portion thereof through which the stem 20 projects. Although not shown in the drawing, the forward end portion of the stem 20 is also engaged by a spring which in turn engages the firing pin of the bolt, all of which is conventional in small caliber rifles, such as 22 caliber rifles. The bolt 23 is provided with a handle 25 which projects laterally therefrom through an opening 26 in one side of the receiver 15. The bolt is also provided with an extractor 27 which is pivotally mounted in a slot 28 and which serves extract and eject spent rounds after firing.

It will be noted that the bolt illustrated is of generally cylindrical configuration while the inner surface of the receiver is also of generally cylindrical configuration. It is pointed out that the rifle illustrated is not adapted for single shot action which requires manual cocking of the trigger after each firing, but is also adapted for semiautomatic firing wherein the cocking is automatic and merely requires the user to manually retract the trigger for each firing.

The bolt 23 is longitudinally shiftable in the receiver during operation of the gun and, of course, is urged forwardly by the action of the helical spring 22. Means are provided for supporting the bolt during its movement in the chamber and this means includes a plurality of substantially identical bearing units 29, as best seen in FIGS. 2 through 5. It will be noted that the bearing units 29 in the embodiment shown are spaced apart from each other and each serves to engage the inner surface of the receiver chamber during movement of the bolt 23 therein. Each bearing unit 29 includes a housing member 30 having a hollow interior 31 and having one closed end and one opened end. The housing member for each bearing unit is also externally threaded as at 32 and threadedly engages an internally threaded bore 33 in the bolt. In this regard, it will be noted that the bolt is provided with a plurality of threaded bores 33, as best seen in FIG. 3, each accommodating one of the bearing units 29.

The closed end of each housing member 30 is provided with a slot 34 therein to permit adjustment of the housing within the associated bore. The slot, will accommodate a conventional screwdriver. A metallic ball element 35 is positioned within the interior 31 of each housing member, and in the embodiment of FIGS. 2 to 5, the ball is engaged by one end of a helical spring 36 which is also positioned within the housing member. The other end of the spring 36 bears against the closed end of the housing and tends to urge a minor circumferential surface portion of the ball exteriorly of the housing member. In this regard, it will be noted that the diameter of the open end of the housing is smaller than the diameter of the interior of the housing member 30. Thus only a minor circumferential surface portion of the ball 35 projects exteriorly of the housing and the outer surface of the bolt and engages the inner surface of the receiver chamber. A small nonmetallic lock element 38 is positioned with a recess within the housing member 30 and projects exteriorly thereof. This lock element is preferably made of plastic and engages the threaded bore to prevent accidental removal of the housing member. The housing member must be forcibly unscrewed to remove the same from the associated'threaded bores.

With this arrangement, the bolt 23 is supported for movement in the receiver chamber by a plurality of the ball elements 35 so that the exterior surface of the bolt is spaced from the interior surface of the receiver. These ball elements not only facilitate movement of the bolt in the receiver chamber but also minimize the need for lubrication for the bolt. It has been found that lubrication of bolt actions under extremely cold conditions often times results in a freezing effect of the bolt in the receiver chamber. This is especially true with respect to automatic firearms used in aircraft which are flying at high altitudes and under extremely cold conditions. Therefore, the use of the bearing units for such bolts substantially eliminates the need for a lubricant and reduces the problems associated with lubricants under these extreme conditions.

It has also been found that the use of bearing units used in larger caliber rifles not only minimizes wear to the parts thereof, but also minimizes the tendency of the bolts to become jammed due to the presence of debris and the like. It is therefore felt that the bearing units have a special utility for military firearms using a bolt action therein especially under combat conditions which result in debris and the like entering the receiver chamber.

Referring now to FIG. 6, it will be seen that a slightly modified form of the bearing unit designated generally by the reference number 290 is there shown. The bearing unit also includes a housing member 30a having a hollow interior 31a and being externally threaded as at 3211 for threaded engagement with the internal bore 33a in the bolt. The closed end of the housing member 30a is provided with a slot 34a to permit adjustment of the housing within the threaded bore. A ball element 35a is positioned within a cup element 3611 which is pressed into the hollow interior of the housing member. It will be noted that the cup member revolvably supports the ball element 35a therein so that only a minor circumferential surface portion of the ball element projects exteriorly through the reduced opening in the cup member and beyond the exterior surface of the bolt. The ball element 35a of each bearing unit engages the inner surface of the receiver in the manner of the embodiment of HO. 5. A nonmetallic lock element 38a is also provided.

Referring now to FIG. 7 it will be seen that a further embodiment of the bearing unit, designated generally by the reference number 29b, is there shown. This bearing unit also includes a housing member 30b having a hollow interior 31b and being externally threaded as at 32b for threaded engagement with the associated internal threaded bore 33b in the bolt. The inner or closed end of the housing member 3012 is provided with a slot 34b to facilitate adjustment of the housing member 30b in the associated threaded bore. A ball element 35b is positioned interiorly of the housing and is revolvably supported by a substantially identical ball element 36b. it will be noted that the ball element 36b positions the ball element 35b so that only a minor circumferential surface of the ball element 35b projects exteriorly or outwardly through the reduced opening in the open end of the housing member 30b and beyond the exterior surface of the bolt. A ball element 35b also engages the inner surface of the associated receiver. The housing member is also provided with a lock element 38b.

Referring now to FIG. 8, it will be seen that a still further modification of the bearing unit is there shown and is designated generally by the reference numeral 290. This bearing unit includes a housing member 30c of hollow construction and defining an interior 31c. The housing member is also externally threaded as at 320 for threaded engagement with a threaded bore 330 in the bolt, the lower end of the housing member having a slot 340 therein to permit adjustment of the housing member with respect to the threaded bore. A ball element 350 is positioned interiorly of the housing member and is revolvably supported therein by a roller 36c which is revolvably positioned within a reduced portion of the interior 310. The roller is revolvable on an axle 370 which projects into radially extending openings in the housing member. It will be noted that the roller 36c revolvably supports the ball 35c so that only a minor circumferential surface portion of the ball projects exteriorly through the reduced opened end of the housing member and beyond the exterior surface of the bolt to engage the inner surface of the receiver. The housing member is also provided with a lock element 380.

Referring now to FIG. 9, it will be seen that the firing pin of a bolt may also be supported for movement in the associated bolt 23 by bearing units 29. In this regard, it will be noted that the bearing units 29 are threaded into suitable internal bores 33 in the bolt so that the associated ball elements 35 project slightly interiorly of the firing pin chamber 40 in the bolt.

These bearing units 29 are identical to the bearing units illustrated in the embodiment of FIG. 5 and will be arranged to engage the firing pin body 42 to completely support the firing pin body for movement in the firing pin chamber. The firing pin 41 projects forwardly from the firing pin body through an opening in the forward end of the bolt in a well-known manner, and the firing pin will be normally urged in a forward position by a suitable coil spring, all of which are well known in the art. By supporting the firing pin with bearing units in the manner illustrated, not only is wear to the firing pin reduced, but this manner of supporting of the firing pin also minimizes any tendency of the firing pin to jam during operation of the g From the foregoing paragraphs, it will be seen that l have provided a novel manner in which the bolt of a gun is supported for movement in an associated receiver so as to substantially obviate the necessity of lubrication for the bolt. Further, by utilizing bearing units, of the type described, in combination with a bolt, the tendency of the bolt to jam is also substantially reduced, if not precluded. Similarly, by utilizing similar bearing units for mounting the firing pin in the bolt, the firing pin also obtains a longer wear life and the tendency of the firing pin to jam or bind is also substantially reduced.

Thus it will be seen from the foregoing description that l have provided a novel bearing unit arrangement for bolts and firing pin in firearms, which is not only of simple and inexpensive construction, but an arrangement which is more efficient than any heretofore known comparable arrangement.

What is claimed is:

l. A gun including a barrel and a receiver, said receiver having a hollow interior defining a receiver chamber,

a bolt slidable in said receiver chamber,

a plurality of similar bearing units mounted on said bolt and engaging the surface of the receiver chamber for supporting the bolt for movement therein, at least some of said bearing units being longitudinally spaced apart, said bolt having a plurality of threaded recesses therein, each bearing unit being mounted within one of said recesses in the bolt and including a threaded hollow housing threadedly engaging its associated recess, a ball in said housing, a ball-engaging element positioned within said housing and revolvably supporting the ball so that only minor circumferential surface portion of the ball projects outwardly beyond the housing and the exterior surface of the bolt to engage the interior surface of the receiver chamber.

2. The gun as defined in claim 1 wherein said ball-engaging element comprises a spring.

3. The gun as defined in claim 1 wherein said ball-engaging element comprises a cup.

4. The gun as defined in claim 1 wherein said ball-engaging element comprises a roller revolvably positioned within said housing and revolvably supporting the ball element.

5. The gun as defined in claim 1 wherein said ball-engaging element comprises a second ball element.

6. The gun as defined in claim 1 and a firing pin longitudinally shiftable in said bolt, and a plurality of said ball bearing units mounted in said bolt and engaging said firing pin to support the same for shifting movement in the bolt. 

1. A gun including a barrel and a receiver, said receiver having a hollow interior defining a receiver chamber, a bolt slidable in said receiver chamber, a plurality of similar bearing units mounted on said bolt and engaging the surface of the receiver chamber for supporting the bolt for movement therein, at least some of said bearing units being longitudinally spaced apart, said bolt having a plurality of threaded recesses therein, each bearing unit being mounted within one of said recesses in the bolt and including a threaded hollow housing threadedly engaging its associated recess, a ball in said housing, a ball-engaging element positioned within said housing and revolvably supporting the ball so that only minor circumferential surface portion of the ball projects outwardly beyond the housing and the exterior surface of the bolt to engage the interior surface of the receiver chamber.
 2. The gun as defined in claim 1 wherein said ball-engaging element comprises a spring.
 3. The gun as defined in claim 1 wherein said ball-engaging element comprises a cup.
 4. The gun as defined in claim 1 wherein said ball-engaging element comprises a roller revolvably positioned within said housing and revolvably supporting the ball element.
 5. The gun as defined in claim 1 wherein said ball-engaging element comprises a second ball element.
 6. The gun as defined in claim 1 and a firing pin longitudinally shiftable in said bolt, and a plurality of said ball bearing units mounted in said Bolt and engaging said firing pin to support the same for shifting movement in the bolt. 